DE102015115167B4 - Shaped body comprising a functional layer, process for its preparation and its use - Google Patents

Abstract

The present invention relates to moldings whose surface is at least partially covered with a functional layer, to processes for producing these moldings and to their use; In addition, the present invention relates to systems - in particular tools - containing the shaped body according to the invention, which have improved stability against abrasive forces.

Description

Technical area

The present invention relates to moldings whose surface is at least partially covered with a functional layer, to processes for producing these moldings and to their use; In particular, the present invention relates to tools coated with a plasma polymer functional layer which has a non-sticking effect with respect to the adhesion of adhesives, e.g. so-called hotmelt and dispersion adhesives. In addition, the present invention relates to systems - in particular tools - which have improved stability against abrasive forces.

State of the art

Shaped bodies or objects which have a plasma-polymer functional layer are known from the prior art. So are already in the German publication DE 42 16 999 A1 Objects made of silver which have a so-called plasma-polymer coating.

Due to a gradual variation of the process parameters, the coatings have a layered structure that includes a coupling layer, a permeation-preventing layer and a hard, scratch-resistant surface seal.

To produce the scratch-resistant layer, a mixture of oxygen and hexamethyldisiloxane (HMDSO) is used.

Furthermore, in the German Offenlegungsschrift DE 195 43 133 A1 discloses a method for producing thin, highly hydrophobic polymer layers by plasma polymerization. For plasma polymerization, monomers are vinylmethylsilane and vinyltrimethoxysilane, which are monomers which have at least one group with a low affinity for oxygen and which can be plasma-polymerized with substantial retention of structure.

The monomers mentioned can nichtpolymerisierbare gases such. As noble gases, nitrogen or hydrogen may be added as auxiliary or carrier gases. Such auxiliary or carrier gases serve to improve the homogeneity of the plasma and to increase the pressure in the gas phase.

The disadvantage of in the DE 195 43 133 In particular, the coating disclosed herein can easily be removed from the substrate, as described above.

Furthermore, the German disclosure document DE 197 48 240 A1 Process for the corrosion-resistant coating of metal substrates described by way of plasma polymerization, wherein the metal substrate is first subjected in a first pretreatment step of a mechanical, chemical and / or electrochemical smoothing and in a second process step of plasma activation, before then the actual plasma polymer coating is applied.

Hydrocarbon and / or organosilicon compounds are mentioned as main constituents of the plasma polymer, with the use of hexamethyldisiloxane and hexamethylcyclotrisiloxane being emphasized as being particularly preferred.

Hexamethyldisiloxane is used in the examples of the abovementioned publication, with oxygen and nitrogen being admixed as auxiliary or auxiliary gases.

More detailed information - such as on the ratio of monomers and oxygen - can not be found in this document. In addition, this publication does not disclose how and on which substrate a plasma polymer coating must be applied in order to obtain a particularly easy-to-clean surface.

In addition, the published US patent publication US 2002/100420 A1 a method for vacuum coating a substrate on the basis of a plasma CVD method, which allows the production of a wear-resistant and friction-reducing multilayer structure of alternating hard material and carbon or silicon monolayers. Carbon sources, such as acetylene (ethyne) or methane, are used as carbon sources for the carbon layers, and silanes, siloxanes and metal silicides are used as silicon sources. To generate and maintain the plasma are taught in the teaching of US 2002/100420-A1 Noble gases - such as argon, neon or helium - used.

As plasma-generating sources are all relevant sources known - such as microwave sources, radio frequency sources, hollow cathode or high current arc.

The multilayer structures produced in this way are suitable, for example, as corrosion and wear protection for tribologically highly stressed components, and in particular as wear protection of components in the dry-running and deficient lubrication area.

Furthermore, the European patent describes EP 1 506 063 B1 also a method for Depositing a coating on a substrate by means of a plasma in an atmospheric or in a sub-atmospheric pressure range or in the low-pressure range by means of a pulsed AC arc discharge. In this case, the atomized coating formation material is composed by any combination of an organic, organosilicon, organometallic or inorganic material.

Description of the invention

The object of the present invention is thus to provide shaped articles-in particular tools-having a functional layer or a functional coating and a method of producing such functionally coated molded articles whose coating has anti-adhesive properties, in particular with respect to adhesives, for example compared with hot-melt adhesives or dispersion adhesives and anti-abrasive properties, so as to be able to minimize the downtime that occurs in industrial production for cleaning (removal of adhesive residue) or for the replacement of defective or worn tools.

• i. Einbringen und Positionieren des Substrats bzw. Formkörpers in einer ADP-(Atmosphärendruckplasma-), NP-(Niederdruckplasma-) oder in eine PACVD-(Plasma Activated Chemical Vapore Deposition-)Anlage;
• ii. Behandeln des Substrats unter Plasmabedingungen des jeweilig gewählten Plasmas, so dass eine Antihaftbeschichtung mit anti-abrasiven zumindest auf einem Teil der Oberfläche des Substrats/Formkörpers ausgebildet wird.

The object is achieved from the basic principle by a shaped body which can be produced by the following method:

• i. Introducing and positioning the substrate in ADP (atmospheric pressure plasma), NP (low pressure plasma) or PACVD (Plasma Activated Chemical Vapor Deposition) equipment;
• ii. Treating the substrate under plasma conditions of the respective selected plasma, so that an anti-adhesive coating with anti-abrasive at least on a part of the surface of the substrate / molded body is formed.

The present invention thus relates to a shaped body according to claim 1, by a method of the aforementioned shaped body according to claim 17 and by a press laminating tool or by a sewing machine containing the aforementioned shaped body according to claim 31. In addition, the present invention relates to the use of the aforementioned shaped body as means for press lamination or for making seams according to claim 32.

Preferred embodiments are objects of the dependent claims associated with the accompanying independent claims.

Plasma technology has established itself in almost all technical areas in recent years. Accordingly, for a variety of embodiments partially extensive state of the art known. In addition to the fine cleaning and the activation of surfaces, plasma technology is particularly suitable for modifying surface properties and for coating surfaces - e.g. with hydrophilic or hydrophobic layers, friction reducing layers or barrier layers. The latter use is particularly relevant for the solution of the above-mentioned objects underlying the present invention, in terms of the coating of components or tools of various kinds (substrate) relevant.

The plasma-assisted coating method according to the invention can be carried out in particular on the basis of three different process variants, including the low-pressure method (low-pressure plasma NP), the atmospheric pressure method (atmospheric pressure plasma ADP) and the so-called PACVD (plasma-activated chemical vapor deposition) method.

In the low-pressure method, a gas is excited in a vacuum by supplying energy, for example by UV radiation. As a result, in addition to electrons and other reactive particles, high-energy ions are generated that form the plasma. For coating such low pressure plasmas of the glow discharge type are used. Here, in a pressure range of 1-100 Pa diffuse gas discharges of 50-1000 mm expansion are generated. Arc discharges are used in a wide pressure range from low pressure to atmospheric pressure and are generally suitable for producing localized plasmas of a few millimeters in size. By means of these hot regions, the gas to be treated can either be flowed for the conversion of gases or the energy is transported from the sheet to the treatment zone by means of a working gas jet (see atmospheric pressure variant below). With a supply of reactive gases they are decomposed in the discharge area and on surfaces in the environment that may belong to workpieces, the layer deposition takes place. The ionized gas chemically reacts with the surface of the substrate. This allows surfaces to be effectively modified or coated.

In the atmospheric pressure variant, a gas is excited by means of high voltage under ambient pressure in such a way that a plasma ignites. The plasma is expelled from the nozzle using compressed air.

By varying the process parameters - e.g. Treatment speed and distance to the substrate surface - as with the low pressure method, the treatment results can be influenced in different directions.

In plasma generation in the atmospheric pressure range, mainly barrier discharges or corona discharges are used, which make it possible to set a non-thermal energy distribution despite the high impact frequency between electrons and heavy particles. In the case of barrier discharge, the self-turn-off of the discharge introduces energy only during a short time window of about 5-50 ns, while the corona discharge creates a highly inhomogeneous electric field by means of sharp or edged electrodes. In both cases, energy is supplied to the electrons only briefly so that only a few shocks can occur.

Plasma Enhanced Chemical Vapor Deposition (PACVD) is a special form of chemical vapor deposition (CVD) that promotes chemical deposition by plasma. The plasma can burn directly on the substrate to be coated (direct plasma method) or in a separate chamber (remote plasma method). While in the CVD the dissociation (breaking up) of the molecules of the reaction gas by external supply of heat as well as the released energy of the following chemical reactions happens, take over this task in the PECVD accelerated electrons in the plasma. In addition to the radicals formed in this way, ions are also generated in a plasma which, together with the radicals, cause the layer deposition on the substrate. As a rule, the gas temperature in the plasma only increases by a few hundred degrees Celsius, which, in contrast to CVD, can also coat more temperature-sensitive materials.

In the direct plasma method, a strong electric field is applied between the substrate to be coated and a counter electrode, by which a plasma is ignited. In the remote plasma method, the plasma is arranged so that it has no direct contact with the substrate. This provides advantages with respect to selective excitation of individual components of a process gas mixture and reduces the possibility of plasma damage to the substrate surface by ions. The plasmas can also be produced inductively / capacitively by irradiation of an alternating electromagnetic field.

In the context of the present invention, the use of a low-pressure or atmospheric-pressure plasma is preferred among the specified embodiments, of which the atmospheric-pressure plasma is particularly preferred. Such a plasma is available with commercially available plasma treatment equipment - such as e.g. with the plant Plasmatreater AS 400 of the manufacturer Plasmatreat GmbH, Steinhagen (DE) - representable.

In the plasma polymerization, vapor-phase organic precursor compounds (precursors or precursor monomers) in the process chamber are first activated by a plasma under the conditions prevailing there. The ionized molecules produced by the activation form first molecular fragments already in the gas phase in the form of clusters or chains. The subsequent condensation of these fragments on the substrate surface then causes a polymerization depending on substrate temperature, electron and ion bombardment and ultimately results in the formation of a closed layer.

Surprisingly, it has been found that by means of the plasma treatment of moldings - preferably using hydrocarbons and / or siloxanes as precursors - coatings can be obtained on the moldings used, which have the desired anti-adhesive effect against adhesives - especially against hotmelt and dispersion adhesives and give the coated tools improved protection against abrasive forces.

Here, the above-mentioned hydrocarbon precursors are short-chain (1 to 10 carbon atoms) saturated or unsaturated hydrocarbons, of which methane, ethane and ethyne (acetylene) are preferred.

In addition, among the hydrocarbons, halo-substituted - especially saturated or unsaturated, cyclic, fluoro-substituted - hydrocarbons - e.g. Hexafluoroethane - preferred. Further, among the cyclic hydrocarbons, octafluorocyclobutane and octafluorocyclopentene are particularly preferable.

Among the polysiloxanes, poly (dimethylsiloxanes) are preferred, including cyclic siloxanes such as hexamethylcyclotrisiloxane. Among the poly (dimethylsiloxanes), hexamethyldisiloxane is particularly preferred.

Furthermore, it is also possible to use mixtures of the precursors mentioned.

Depending on the particular precursors used, it may be advantageous to use the substrate - i. Shaped body or tool - to heat during the coating.

The gases to be used as process or ionizing gases are also known from the prior art. They include gases or noble gases - such as argon, oxygen and / or nitrogen -, or gas mixtures - such as air or compressed air - or forming gas (a gas mixture of 95% nitrogen and 5% hydrogen).

The gas molecules are ionized in the (vacuum) treatment plant, where a plasma is generated by an electric field. The plasma for treating plastics is preferably produced by means of microwave radiation and high-frequency alternating voltage, while in the plasma coating of substrates made of metal preferably a pulsed DC plasma is used.

Examples:

The following exemplary plasma parameters represent the plasma conditions for a carbon-based and a siloxane-based coating, respectively:

A) Apparatus parameters

Free jet nozzle made of tungsten and copper, d ~ 4mm

Pulsed AC arc discharge (AC arc discharge) with target corridor:

• - Active power ~ 300 W (RMS voltage ~ 1 kV, RMS current 0.3 A)
• - ~ 2 pulses per period, peak ~ 3.8 kV, pulse width ~ 1.4 μs
• - Tolerant deviation approx. +/- 25% (achievable with a Plasmatreater AS 400 system)
• Plasma voltage: 280V
• - Plasma frequency: 21 kHz
• Plasma Cycle Time: 10-20%

B) Exemplary layer formulation for an organic carbon-based layer:

• - Ionizing gas: nitrogen (~ 1500 l / h)
• Precursor: acetylene (~ 38 l / h), 1-point feed
• - Distance nozzle exit substrate: 5-10 mm
• - Surface (meandering) coating with track pitch: 1 4 mm (per layer thickness)
• Jet speed: 5-10 m / min (per layer thickness)
• - Optional: tempering e.g. at 200 ° C for 1.5 h to improve the layer adhesion / immediate use.

C) Exemplary layer formulation for siloxane-based layer:

• - Ionizing gas: compressed air (~ 1500 l / h)
• Precursor: hexamethyldisiloxane (~ 30 g / h), 1-point feed
• - nozzle exit substrate distance: 5-10 mm;
• - Surface (meandering) coating with track pitch: 1-4 mm (per layer thickness)
• Jet speed: 20-80 m / min (per layer thickness)
• - Optional: tempering e.g. at 200 ° C for 1.5 h to improve the layer adhesion / immediate use.

Claims (32)

 Shaped body with an antiabrasive non-stick coating against hot melt adhesives and / or dispersion adhesives producible by Treating the uncoated molded product with a plasma in a plasma treatment apparatus comprising a tungsten-copper free jet nozzle, with a diameter of ~ 4mm, with a pulsed AC arc discharge in a target corridor with an active power of ~ 300 W at an effective voltage of ~ 1 kV and a RMS current 0.3 A with ~ 2 pulses per period with a peak voltage of ~ 3.8 kV and a pulse width of ~ 1.4 μs with a tolerant deviation of +/- 25% and a plasma voltage of 280 V with a plasma Frequency of 21 kHz and a plasma cycle time of 10-20% in the presence of an organic or silicon-organic precursor selected from a group comprising short-chain hydrocarbons having 1 to 10 carbon atoms and polysiloxanes in the presence of a process and / or ionizing gas. Shaped body according to claim 1, characterized in that the shaped body is a tool. Shaped body according to claim 2, characterized in that the tool is a cover device or a sewing knife. Shaped body according to one of claims 1 to 3, characterized in that the plasma is a low-pressure plasma or an atmospheric pressure plasma or the treatment is carried out with a plasma-assisted chemical vapor deposition. Shaped body according to one of claims 1 to 4, characterized in that the organic precursor is a short-chain saturated or unsaturated aliphatic hydrocarbon precursor. Shaped body according to claim 5, characterized in that the hydrocarbon precursor is selected from the group comprising methane, ethane and ethyne. Shaped body according to one of claims 1 to 4, characterized in that the organic precursor is a saturated or unsaturated halogenated hydrocarbon. Shaped body according to claim 7, characterized in that the precursor is selected from the group comprising hexafluoroethane, octafluorocyclobutane and octafluorocyclopentene. Shaped body according to one of claims 1 to 4, characterized in that the silicon-organic precursor is a poly (dimethylsiloxane). Shaped body according to one of claims 1 to 4, characterized in that the silicon-organic precursor is selected from the group hexamethylcyclotrisiloxane or hexamethyldisiloxane. Shaped body according to one of claims 1 to 10, characterized in that the ionizing gas is selected from the group comprising oxygen, nitrogen and gas mixtures and noble gases. Shaped body according to claim 11, characterized in that the gas mixture is selected from the group comprising air, compressed air and forming gas. Shaped body according to claim 11, characterized in that the noble gas is argon. Shaped body according to claim 1 and 11, characterized in that the ionizing gas is nitrogen and is fed into the plasma chamber at a rate of ~ 1500 l / h and the precursor is ethyne, which is fed into the plasma chamber at a rate of ~ 38 l / h is, wherein the distance from the nozzle exit to the substrate in a range of 5 to 10 mm and a flat, meandering coating having a layer thickness in a range of 1 to 4 mm at a jet speed in a range of 5 to 10 m / min. Shaped body according to one of claims 1 and 12, characterized in that the ionizing gas is compressed air and is fed into the plasma chamber at a rate of ~ 1500 l / h and the precursor is hexamethyldisiloxane, which is introduced at a rate of ~30 g / h into the plasma space Plasma space is fed, wherein the distance from the nozzle exit to the substrate in a range of 5 to 10 mm and a flat, meandering coating with a layer thickness in a range of 1 to 4 mm at a jet speed in a range of 20 to 80 m / min he follows. Shaped body according to claim 1, characterized in that in a further reaction step, a heat treatment at 200 ° C over a period of 1.5 h.  A process for producing a shaped article having an anti-abrasive non-stick coating against hot melt adhesives and / or dispersion adhesives according to one of claims 1 to 16, comprising the following method steps treating the uncoated molded article with a plasma in a plasma treatment apparatus comprising a tungsten-copper free jet nozzle having a diameter of ~ 4mm with a pulsed AC arc discharge) in a target corridor with an active power of ~ 300W at an RMS voltage of ~ 1kV and an RMS current of 0.3A with ~ 2 pulses per period at a peak voltage of ~ 3.8kV and one Pulse width of ~ 1.4 μs with a tolerant deviation of +/- 25% and a plasma voltage of 280 V with a plasma frequency of 21 kHz and a plasma cycle time of 10-20% in the presence of an organic or silicon-organic precursor selected from a group comprising short-chain hydrocarbons having 1 to 10 carbon atoms and polysiloxanes in the presence of a process and / or ionizing gas. A method according to claim 17, characterized in that the plasma used in the method is a low pressure plasma or an atmospheric pressure plasma or the coating is carried out with a plasma-assisted chemical vapor deposition. Method according to one of claims 17 or 18, characterized in that the organic precursor is a short-chain saturated or unsaturated aliphatic hydrocarbon precursor having 1 to 10 carbon atoms. A method according to claim 19, characterized in that the hydrocarbon precursor is selected from the group comprising methane, ethane and ethyne. Method according to one of claims 17 or 18, characterized in that the organic precursor is a saturated or unsaturated halogenated hydrocarbon. A method according to claim 21, characterized in that the precursor is selected from the group comprising hexafluoroethane, octafluorocyclobutane and octafluorocyclopentene. Method according to one of claims 17 or 18, characterized in that the silicon-organic precursor is a poly (dimethylsiloxane). A method according to claim 17 or 18, characterized in that the silicon-organic precursor is hexamethylcyclotrisiloxane or hexamethyldisiloxane. Method according to one of claims 17 to 24, characterized in that the ionizing gas is selected from the group comprising oxygen, nitrogen and gas mixtures and noble gases. A method according to claim 25, characterized in that the gas mixture is selected from the group comprising air, compressed air and forming gas. A method according to claim 25, characterized in that the noble gas is argon. A method according to claim 17, 20 and 25, characterized in that the ionizing gas is nitrogen and is fed into the plasma chamber at a rate of ~ 1500 l / h and the precursor is ethyne, which at a rate of ~ 38 l / h in the Plasma space is fed, wherein the distance from the nozzle exit to the substrate in a range of 5 to 10 mm and a flat, meandering coating with a layer thickness in a range of 1 to 4 mm at a jet speed in a range of 5 to 10 m / min he follows. A method according to claim 17, 24 and 26, characterized in that the ionizing gas is compressed air and is fed into the plasma chamber at a rate of ~ 1500 l / h and the precursor is hexamethyldisiloxane which is introduced at a rate of ~30 g / h into the plasma space Plasma space is fed, wherein the distance from the nozzle exit to the substrate in a range of 5 to 10 mm and a flat, meandering coating with a layer thickness in a range of 1 to 4 mm at a jet speed in a range of 20 to 80 m / min he follows. A method according to claim 17, characterized in that in a further reaction step, a heat treatment at 200 ° C over a period of 1.5 h.  Press laminating tool or sewing machine containing a shaped body according to one of claims 1 to 16.  Use of a shaped article according to one of Claims 1 to 16 as a means for press lamination or for the production of seam connections.